Aluminium alloys



Patented May 5, 1936 UNITED STATES PATENT OFFICE,

ALUMINIUM ALLOYS Josef Schulte, Bonn-on-the-Rhine, Germany, assignor to Vereinigte Leichtmetallwerke Gesellschaft mit beschrankter Haftung, Bonn-onthe-Rhine, Germany, a corporation of Germany No Drawing.

Application March 1, 1935, Serial No. 8,80 In Germany March 2, 1934 2 Claims. (01015-142) This invention relates to aluminium alloys.

It is known that aluminium alloys with low to 1.5%. It has also been proposed to increase the magnesium content of such alloys to about Endeavours are however still being directed to improving still further the mechanical properties of these alloys, particularly for the purpose of saving weight in aircraft construction. In this connection, not only an increase in breaking strength, but also the raising of the elastic limit and yield point come into consideration. These properties can of course be improved to a certain extent by cold working, because the resulting consolidation also raises the yield point. Such procedure, however, can be applied to only a limited extent in practice, .because elongation and capacity for undergoing deformation by mechanical treatment are naturally considerably lessened thereby. It is therefore a point of special importance, especially in the case of moving vehicles, to arrive at an improvement in the mechanical properties by suitably compounding the alloys.

It has now been ascertained, bycomprehensive experiments, that particularly good results are furnished by alloys of the following composition- Percent Copper 3 to 5 Magnesium 1.3 to 1.4 0 Silicon 0.4 to 0.7

Manganese 1.25 to 1.45 Aluminium Remainder These alloys differ substantially from already 5 known alloys by an accurately harmonized content oi manganese, and also by a further increase in the magnesium content.

alloy containing for example:

For example, an alloy containing:

Percent Copper 4.0 Magnesium- 1.35 Silicon 0.65 Manganese 1.3 Aluminium Remainder after annealing at temperature of 510, quenching and storing for 6 days, exhibits the following values:

Yield point 33 to 36 kgs. per sq. m. Tensile strength 48 to 54 kgs. per sq. mm. Elong 14 to 18% For comparison, it may be stated that a known Percent Copper 4.0 Magnesium 1.2 Silicon 0.7 Manganese 1.2 Aluminium Remainder on being hardened in the same manner, exhibited gation of 18 to 19%.

As is evident from the comparison of these data the yield point-a highly important technical property in aviationis very notably increased by the new composition of the alloys. The very slight reduction in the elongation is of no moment. and is also counterbalanced by the not inconsiderable increase in tensile strength.

I claim:

1. An aluminium alloy, which is age-hardenable by annealing, quenching and aging at room temperature, consisting of 3 to 5% of copper, 1.3 to 1.4% of magnesium, 0.4 to 0.7% of silicon and 1.25 to 1.45% of manganese, the remainder being aluminium.

2. An aluminium alloy as set forth in claim 1, consisting of 4% of copper, 1.35% of magnesium,

0.65% of silicon and 1.3% of manganese, the re- 

